The present invention is directed to a hydraulic control system especially designed to coordinate the rate of rotation of a workpiece about a fixed axis with the rate of movement of a cutting tool radially across the end face of the rotating workpiece so that the cutting speed or rate of movement of the workpiece past the tool remains constant at all times.
It is well known that for a given metal machining operation, there is an optimum cutting speed which results in the most efficient compromise between cycle time, tool life and cutting efficiency. The maintaining of a substantially constant cutting speed presents a problem in the case where an end facing operation is performed on a rotating workpiece by advancing a cutting tool radially across the face toward the axis of rotation. Assuming a constant rotary speed of the workpiece, the linear speed of the workpiece past the tool at the point of contact between the tool and workpiece is directly proportional to and varies with the radial distance between the tool and the axis of rotation of the workpiece. While various mechanisms or control systems have been devised to achieve a constant cutting speed in an end facing operation, such systems typically require the employment of complex mechanisms or electrical control circuitry.
The present invention is directed to a control system designed to achieve a constant cutting speed in an end facing machining operation which may be produced, installed and maintained at a relatively low cost and which will maintain a constant cutting speed in a simple and fool proof manner.